Perhaps you should try some spelling variations:
sach nganh » sach ngan, cac nganh, cach nhanh
sach tranh » canh tranh
sach danh » sach dao, sach dung, sach kinh
cong khi » cong thai, khong khi, co khi
vu sach » vu bach, su sach, vu khach
tranh y » trinh y, tranh o, tranh 30
y khi » ly khi, ky khi, my khi

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: (( vu sach tranh y khi đong luc ) OR ( vu ((sach nganh) OR (sach danh)) cong khi đong luc ))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( vu sach tranh y khi đong luc ) or ( vu ((sach nganh) OR (sach danh)) cong khi đong luc ))~".
• Adding a wildcard symbol may retrieve word variants: (( vu sach tranh y khi đong luc ) or ( vu ((sach nganh) OR (sach danh)) cong khi đong luc ))*.